Treatment of wood and like porous material



Jam 22, 1929. 1,699,635

M. SMITH TREATMENT OF WOOD AND LIKE POROUS MATERIAL Filed Dec. 29, 1925 BYJ-Eu H O R NET-S Patented Jan. 22, 1929. I

UNITED STATES mon'ron smrn', or STAPLEFORD, ENGLAIiD.

TREATMENT OF WOOD AND LIKE POROUS MATERIAL.

Application filed December 29, 1925, Serial No.

This invention comprises improvements in the method of treating wood and like porous material and has particular, although not exclusive, reference to the treatment of wood to be utilized in the manufacture of lead and similar pencils.

The principal object of the invention 1s to provide an improved method of and means for seasoning and softening wood of varied kinds and like porous materials and in particular means for seasoning and softening wood of varied kinds, which are not naturally suitable for use in the manufacture of lead and like pencils, and by such treatment render the Wood particularly adaptable for such manufacture.

Another object of the invention is so to treat the wood as to inhibit warpingtherein and in articles made therefrom,

A further object of the invention is to enable, by the improved seasoning and softening process, freshly cut or green wood to be utilized for lead and like pencil making; while a further object is to produce in the treated wood, evenly and uniformly throughout its mass, a desirable and pleasing tint.

Heretofore,.it has been proposed to treat wood by subjecting same to the action of air heated to a relatively high temperature but experience has proved that While such treatment effects a browning of the wood the requisite softening is not produced, neither is it possible to treat satisfactorily green wood in this way particularly when employed in the manufacture of pencils, as wood subjected to such treatment is liable to be rendered irregular and uneven, and the treatment is often destructive to the wood. v

The principal feature of the present invention consists in the treatment of wood or like porous material by impregnating same with the vapour or vapours of softening media.

The primary purpose of this treatment is to soften the wood or the like but an effect consequent upon or incidental to the treat- 78,190, and in Great Britain August 17, 1925.

in treating wood or the like by subjecting it to and/or causing it to be impregnated wholly or partially by a softening medium or mediums such for example as soap solution, Turkey red oil, oil emulsion, or other -con venlent or approved oleaginous matter and in subsequently vapourizing or partially vapourizing (preferably at a comparatively high temperature) the softening medium or mediums employed so that the vapours from the softening media penetrate the wood. A suitable emulsion forimpregnatin'g the wood is 18% "emulsion of Turkey red 'oil in Water.

The invention may conveniently be applied by treating wood or the like in three steps or stages, firstly, initially drying-the-Wood conveniently by subjecting same to the action of hot air at a suitable temperature and humid-- ity; secondly, treating the dried wood with a suitable softening medium so as to cause said medium to penetrate wholly or partially into the wood and thirdly, subjecting the wood so treated to a final heating by hot air at a comparatively higher temperature so as f to vapourize the softening medium.

In vapourizing the softening medium it is assumed that the oily vapour therefrom impregnates the Wood or the like and produces the same desirable effects as if the wood had actually been impregnated with the oil or softening medium, but all undesirable effects are eliminated. One of the undesirable effects in the present known method of treating wood with oil or similar softening medium for use in the manufacture of pencils is that the oil acts as a deterrent to the gluing together of the wood parts or slats forming the pencil. By the present process, however, this disadvantageis overcome, and a further feature, therefore, may be said to reside in the provision of means for producing wood having oil impregnated characteristics and which will eflectively take glue or the like for adhering purposes. V

- The treatment of wood as above, in addition to eifectively seasoning and softening same, produces an even and uniform tinting of' the wood throughout the entire body thereof. The term softening as used in this specification does not refer in any way to supplev.ness of the wood and by way of illustration it may be said that a Wood that has been treated in accordance with this invention is softened in that it can be. cut more readily.

The present invention is therefore distinctand separate from processes of treating the wood which render the wood more supple and more readily moulded.

For the purpose of more fully describing the nature of this invention reference will now be made to the accompanying drawings,

wherein 4 Fig. 1 illustrates in side elevation a portion of an apparatus applicable for use in carrying out an initial drying of the wood or the like in the treatment according to the present invention.

. Fig. 2 illustrates in side elevation acontinuation of the apparatus shown in Fig. 1. 6

Fig. 3 illustrates in side elevation another part of apparatus applicable. for use in carrying out this invention.

In one, convenient method of carrying out. the invention, as applied to the treatment of wood for use in the manufacture of pencils,

*' in an opposite direction to the travel of the wood. 3

The air is heated by passing same through an air heating chamber 4; prior to its passage through'the drying chamber 1, said chamber v 4; containing suitable electric or other heating elements by which the airin passing through the chamber is heated. Asuitable blowing fan 5 located at the air inlet endof heating chamber 4 functions to force air through said chamber and the drying chamber or oven 1.

The temperature of the hot air when en tering the chamber in the first or drying op-' .eration is advantaigeously in the neighorhood of 220 to 260 i said air being rendered increasingly humid, by its passage across the slats undergoing treatment. It will be appreciated that the temperature of the air gradually decreases and itsrelative humidity increases as same travels along the chamber 1, the wood thereby meeting a gradually increasing-heat and decreasing humidity during its movement to the. delivery end of the chamber.

This initial drying of the wood slats-may, under certain circumstances, be .dispensed with. i i P A-fter the initial drying of the wood slats b n the hot air (if such initial drying is efiected samegare delivered from the drying chamber 1 by any suitable evacuating means and, suitably fed into an impregnating chamber or vessel-8 into which is introduced a softening liquid i. e. any suitable'liquid or medium haying asoftening effect on wood. This liq-- ui-d or medium is caused by any known or suitable means, such as a vacuum, to penetrate the surface of the.woo

- r The production of a vacuum in the impregnating chamber 8 may be effected by means of a vacuum pump such as 9 which, when the chamber 8 has received the requiredquanti- I ty of Wood slats and has been sealed to the outer atmosphere, is set in motion to withdraw the air through the pipe 10. A drain pipe 11 with cock 12 may be'furnished for Idraining superfluous liquid from the cham- 7 er 8. The wood slats after the partial impregnation are transferred to a hot air chamber similar to the chamber 1 in "which the initial drying is effected, but working at a higher temperature cycle. The purpose of this final r heating at a comparatively high temperature is to effect a vapourizing of the softening medi'um to cause the vapour (preferably of an oleaginous'nature) to penetrate the Whole mass or body of the wood. Thisefliec'ts a uni Q form softening 'ofthe wobd and also causes same to be tinted to a rich and'pleasing colour evenly .and uniformly throughout the mass.

The temperature of the final heating chamber controls the extent of vaporization, and wood treated in accordance with this inven 'tion is free from objectionable properties due to apparent retention of themedium, so that in this respect for practical purposes the medium is in effect driven ofi' while owing to the efl'ectant result of the process complete driv ing off of the medium in the usual sense of the term cannot be accepted.

While no definite theory-is advanced of the process, the advancement of such a theory not 1 ein thoughtnecessary for a proper under-- stan ing of the invention, and the physical mechanism of the process being apparently so complex that it is not desired to restrict the application by virtue of the process being interpreted with reference to such a theory, it is suggested that in vaporizing the I softening f medium as above described the vapor thereof impregnates the wood or other substance 'by a' process of'absorption by, or

passing through, the cellulose structure of the wotui' and thereby softens the wood and,

imparts to it the desired properties outlined herein. 1

Further, it is to be understood that the expression vaporization as applied to the softening medium in this specification e n-. braces both complete and partial vaporization. a For exam 1e, wood heated'with cod-oil emulsion is subjected to a final heat treatment of, say 230" 240 F. This is not suflicient to efi'ect vaporization of cod oil per se but it is found in 'accordanee with the present process that the oil completely penetrates the wood in company with the water and for this reason treatment the wood is so effected that warping therein and in articles made therefrom is inhibited.

Another desirable effect obtained by the treatment in accordance with this invention is that pieces of wood such for example as wood slats, which although of the same or similar species have before treatment different properties such for example as degree of hardness and tint or colour, are rendered more uniform in regard to these properties. Further in the carrying out' of the present invention the results obtained and particularly the change in the aforementioned properties of the wood can be readily varied within comparatively wide limits to meet existing requirements by varying the nature of oil or other softening medium employed, and where oil emulsion is utilized, by varying the per centage of oil in such emulsion, as also by varying the degree of evaporation of said oils or the like in the wood.

Additionally, wood treated by the process in accordance with the present invention is effectively seasoned, softened and tinted and rendered ready for use in a far more expeditiobus manner than has heretofore been possi le.

7 Claims 1. The treatment of wood and like porous material by impregnating said wood to a suitable extent with softening medium (preferably of an oleaginous nature) and subsequently subjecting the impregnated wood to heat sufficient to vapourize the softening medium and cause the vapourthereof to impregnate the wood.

2. The treatment of wood or like porous material, which consists in impregnating the same to a predetermined degree with a softening medium and subsequently vaporizing said medium so that the vapor thereof impregnates the wood by a process of absorption by or passing through the cellulose structure of the wood and thereby softens the wood.

3. In the treatment of wood and like porous material initially drying the wood by subjecting same to the action of hot air, partially impregnating the dried wood with a softening medium (preferably of an oleaginous nature) and finally vapourizing the softening medium at a comparatively high temperature.

4. In the treatment of wood and like porous material, initially drying the wood by the action of hot and humid air, partially impregnating the dried wood with softening medium (preferably of an oleaginous nature) under the influence of a vacuum and finally vapourizing said softening medium at a comparativelv high temperature to cause same to penetrate the wood.

MORTON SMITH. 

